Unkillable Tools · No.2
Build a cost, quote or pricing calculator here. Export one HTML file and paste it into your site. No script tag pointing at our servers. No monthly impression limit. Nothing to cancel, because there is nothing to subscribe to.
0 external requests · 0 dependencies · 0 accounts · works offline
Everything you see is produced by the same code you download. There is no separate “published” version.
Every subscription calculator builder embeds a script tag or an iframe that points at their server. That is not a technical detail — it is the business model. It is also the failure.
Plans are metered in “monthly impressions”. One builder's own documentation states that once you run out, your embedded calculator “will appear as a button on your website.” Your lead generator fails on your best traffic day.
Cancel, miss a card renewal, or let a trial lapse and the widget goes blank — on a page you still own, in a design you paid for. The page stays up. The calculator doesn't.
An acquisition, a pivot, or a shutdown takes every calculator with it. You cannot self-host your way out, because you were never given the thing in the first place.
A file. That's the whole idea.
Markup, styles and logic in a single block of HTML — about 21 KB. No jQuery, no framework, no CDN, no build step. Open it in a text editor and read every line.
Zero network requests at runtime. Your visitors' numbers are never transmitted, so there is no third-party processor to declare in your privacy policy and nothing to leak.
Formulas are parsed into a syntax tree and walked — never eval'd. That means the export
runs on locked-down corporate and e-commerce sites where script-tag widgets get blocked.
Pricing and limits below are the publicly listed figures for hosted calculator builders as of July 2026.
| Hosted builders | Unkillable Calculator | |
|---|---|---|
| Cost | $5 – $115 / month, forever | Free, or $29 once for Pro |
| View limit | 500 – 75,000 impressions / month | Unlimited |
| If you stop paying | Calculator stops working | Keeps working |
| If the company shuts down | Calculator stops working | Keeps working |
| Where it runs | Their server | Your page |
| Visitor data | Passes through a third party | Never leaves the browser |
| Works offline / on an intranet | No | Yes |
| Account required | Yes | No |
| Editable by you afterwards | Only inside their dashboard | It's your HTML |
Ten years of the cheapest hosted plan costs about $600. Ten years of this costs $29, and the tenth year does not depend on us still existing.
The free tier is not a trial. It never expires, and what it exports is genuinely yours.
Unlimited calculators, forever
Yours for good. No renewal.
One payment. Not a subscription.
Building for clients? Pro covers unlimited sites — one payment covers every calculator you ever ship.
Each of these ships a complete working calculator you can load into the builder and make your own.
Nothing at all. That is the entire point of the product. The exported file contains its markup, its styling and its logic, and it never contacts us. If this site disappeared tomorrow, every calculator built here would carry on working exactly as it does today. You can verify this before you trust it: disconnect from the internet and open your exported file.
No, and there structurally cannot be. The file is served by your website, so there is nothing on our side to count. Hosted builders meter impressions because their servers render the widget on every page view — that is what you are actually paying for each month.
No. The builder runs entirely in your browser. Nothing you type here is transmitted, stored or logged. Open your network tab and watch — the only request is for the page itself.
Yes, and on hand-written HTML, Ghost, Notion embeds, HubSpot, an intranet, or a file on a USB stick. It is plain HTML with inline CSS and JavaScript, so it goes anywhere HTML goes. The Export tab lists the exact block to use on each platform.
Two ways. Save the project as a .json file, reopen it here later and re-export — that is the easy path.
Or edit the HTML directly, because it is readable and it is yours. Neither route needs our permission or our servers.
The form posts to your endpoint, not ours. Either it opens the visitor's email app with the quote pre-filled, or it POSTs to a form service you already use (Formspree, Basin, your own handler). The submission includes the numbers the visitor entered, so you receive the quote and the contact together.
We never see it, and we could not see it even if we wanted to — there is no code of ours running on your site that could.
One small credit line under the calculator, and the three business features: lead capture, printable quotes and conditional fields. The maths, the design control, the templates and the export are all unrestricted. A free calculator is a real, permanent, fully working calculator — not a trial that stops.
The formula engine ships with a test suite covering operator precedence, right-associative powers, ternaries, rounding, currency formatting and every built-in function, plus a check that each shipped template computes correctly. The loan template is verified against the standard amortisation reference figure.
Your licence key works on unlimited devices. Enter it below and it activates locally.
Each one is a complete working calculator. Load it, then change anything.
One payment, yours permanently, unlimited sites.